PM
4/27/09
Block C Problem 3.3 and Follow Up Big Idea Negative numbers help us to model many real world situations.
Essential Question #3: How do I find the difference between integers?
Studying and describing patterns is important in math. Study the patterns in the equations below, and then work on the problem.
15-5=10
15-4=11
15-3=12
15-2=13
15-1=14
15-0=15
A. Describe any patterns you see in the way differences change as the integers subtracted from 15 get smaller.
One pattern is that the more you subtract from 15 the difference will get more and more less, and if your subtract 0 then the difference will be 15 because your aren’t taking anything away.
B. Use the patterns you observed to predict the answer to 15- -1. Check your prediction using a number line or a chip board.
Subtract -1=16
I think that 15- -1 is 16. Black= +1 and Red= -1
C. Predict the answer to 15- -4. Explain your reasoning. 15- -4=19, because subtracting a negative number from a positive is like adding a positive.
FOLLOW UP 1. Study the equations below.
-10-5=-15
-10-4=-14
-10-3=-13
-10-2=-12
-10-1=-11
-10-0=-10
A. Describe any patterns you see in the way the differences change as the integers subtracted for -10 get smaller.
The pattern is that the bigger the number that is subtracted from -10 the smaller the difference will be.
B. Use the patterns you observed to predict the answer to -10- -1. Check your answer with a chip board or number line.
Subtract -1 and get -9
-10- -1=-9 Black= +1 Red= -1
C. Predict the answer to -10- -6. Explain your reasoning.
-10- -6= -4, because if you subtract a negative from a negative the number increases.
2. When you add 2 negative integers, you get a negative sum. When you subtract 2 negative integers, do you always get a negative difference? Explain.
No, because subtracting a negative integer is like adding a positive integer.
4/27/09
Block C
Problem 3.3 and Follow Up
Big Idea
Negative numbers help us to model many real world situations.
Essential Question #3: How do I find the difference between integers?
Studying and describing patterns is important in math. Study the patterns in the equations below, and then work on the problem.
15-5=10
15-4=11
15-3=12
15-2=13
15-1=14
15-0=15
A. Describe any patterns you see in the way differences change as the integers subtracted from 15 get smaller.
One pattern is that the more you subtract from 15 the difference will get more and more less, and if your subtract 0 then the difference will be 15 because your aren’t taking anything away.
B. Use the patterns you observed to predict the answer to 15- -1. Check your prediction using a number line or a chip board.
C. Predict the answer to 15- -4. Explain your reasoning.
15- -4=19, because subtracting a negative number from a positive is like adding a positive.
FOLLOW UP
1. Study the equations below.
-10-5=-15
-10-4=-14
-10-3=-13
-10-2=-12
-10-1=-11
-10-0=-10
A. Describe any patterns you see in the way the differences change as the integers subtracted for -10 get smaller.
The pattern is that the bigger the number that is subtracted from -10 the smaller the difference will be.
B. Use the patterns you observed to predict the answer to -10- -1. Check your answer with a chip board or number line.
C. Predict the answer to -10- -6. Explain your reasoning.
-10- -6= -4, because if you subtract a negative from a negative the number increases.
2. When you add 2 negative integers, you get a negative sum. When you subtract 2 negative integers, do you always get a negative difference? Explain.
No, because subtracting a negative integer is like adding a positive integer.